You should know this by now: Computers can and do fail. And nasty viruses can take down your system by creeping through your antivirus software and firewall.

The problem is that you usually get no warning before it’s too late. Puff! Your data is gone.

This has happened to more than a few businesspeople. In extreme cases, it has put companies out of business. And the worst part is this: It’s completely avoidable. By backing up your data, you can retrieve all or most of what you lose.

Yes, yes, I hear some of you snickering about the hassle involved. Indeed, there is a hassle involved. But you owe it to yourself — and your business — to take stock of your backup plan (or lack thereof) by reviewing these tips.

Most Important: Back up Your Customer Databases and Payroll Records

What’s the heart and soul of your company? People have different opinions, but certainly your customer or client database has to rank high.

Inside one or two data files are all the nitty-gritty details including what they buy, when they buy, how they pay and so forth. Contact lists also are databases, and you might have yours combined with your customer list.

So, where would you be if you lost your database? How would you feel if you attempted to open your database and it wasn’t there? Not good, I’ll bet. So you should be backing up your database.

Also mission-critical for backups are your employee payroll records. You don’t want to lose the information that you have to report to the Internal Revenue Service. Your employees don’t want problems with the IRS, either. And they certainly don’t want to be paid late.

Protect Your Registry Settings

You should be backing up all of your data. But if you don’t, a third item you should have high on your priority list for regular backups is your Windows Registry. This is the huge database that tells your computer how to run. Without it, you have an expensive paperweight.

Most backup programs allow you to back up the Registry automatically. If not, you can easily do it manually. Here’s how:

• Click Start > Run.
• In the box, enter “regedit” (without the quotes). Click OK.
• In the Registry, click File > Export (or Registry > Export Registry File in Windows 98). Navigate to your backup medium. It will probably be drive E:.
• Name the file and click Save.

You don’t need to back up Windows or your applications, such as Microsoft Word. If the worst happens, you can always re-install those programs. But the information you create must be protected.

Store Your Backups Off-Site

To really be safe, the backup medium (tape, CD or DVD, etc.) should be removed from your site. If you are backing up to tape, for instance, and you leave the tape cartridge in the machine, you’ll be protected if the hard drive fails. But if the equipment is stolen, or the office burns to the ground, the backup will be lost.

The safest procedure is to use a different tape or disk each day. Keep all but the current day’s media off-site — at your home, perhaps.

Forget About Doing Backups With Floppies

The earliest backup medium was the floppy. These are no longer practical. They hold only 1.4 megabytes of data, so a large collection would be needed for a backup. You would have to sit at the computer for hours, swapping the floppies in and out. Don’t even think about it.

Tape has been the medium of choice for a number of years. Tape backups are relatively slow, but the process can be automated. You can schedule the backup for when you’re sleeping.

Tape drives have a capacity of 10 to 40 gigabytes, with the data uncompressed. Most advertise that they’ll hold twice as much if the data is compressed. It’s true that they can hold more compressed data, but you’re unlikely to get double the storage. Some file types just don’t compress.

Most tape drives cost several hundred dollars. Tapes are relatively expensive, too. And the software can be difficult. Tape is a great backup medium, once you understand it. It has its drawbacks in terms of the time and work involved. But once you get a system down, it can go smoothly.

Here are some other options:

• Back up to a burner — a CD or DVD drive. Neither holds nearly as much data as a tape. If you decide to go this route, be sure your software allows automated backups. A CD or DVD will work well if your data is not voluminous. CDs will hold up to 700 MB; most DVDs will hold 4.7 GB.
• Use a Zip or Jaz drive. These are made by Iomega. Zips hold 250 MB of data; Jaz holds 2 GB.
• Use an external hard drive. These run U.S. $200-$300 and hold a vast amount of data. They attach to the computer via high-speed connections such as USB 2.0 or FireWire. Hard drives are fast, so the backup wouldn’t take much time. But an external hard drive is relatively bulky, so you would get tired of taking it home.

Another Option to Consider: Backing up on an Internal Hard Drive

You could use a second internal hard drive, although that would mean leaving the backup in the office. Massive hard drives can be had for less than U.S. $100. Windows automatically accommodates multiple hard drives. You could simply copy your data from the master hard drive to the second one, known as a slave.

If you’re handy, you can install a second hard

drive yourself. Having a shop retrofit a computer wouldn’t be especially expensive. Or, if you’re buying a new computer, order it with two hard drives.

If having two hard drives appeals to you, consider a RAID system. RAID means Redundant Array of Inexpensive Disks. RAID systems can be immensely complicated. But a two-disk system is not; you set it up as a mirror.

When you save something, it automatically saves to both drives. The second drive looks just like the first. So if one fails, you have a perfect copy. And RAID will automatically switch you over to the working drive.

Some motherboards have RAID capability built in. If yours doesn’t, a RAID card can be added to the computer.

However, a RAID system would leave your backup inside the computer. That leaves you vulnerable to fire or theft.

Need More Security? Consider an Online Backup Service

If you’re especially concerned about safety, you might want to consider an Internet backup. There are many firms on the Web that will store your data for you, for a monthly fee. You can run the backup automatically.

Most analysts recommend that only businesses with a high-speed Internet connection consider this option, because backups by dial-up modem could tie up your phone lines for several hours at a time.

Also, Microsoft Windows SharePoint Services — which enable you to build a private intranet or extranet site for your business — offer the ability to store copies of your most-vital business documents in a secure area that you can access through the Internet.